Implement for measuring the hardness of metals



P. P. ROUDIE June 10, 1930.

IMPLEMENT FOR MEASURING THE HARDNESS OF METALS Filed Oct. 21. 1927 III) Patented June 10, 1930 PATENT OFFEQE PIERRE PAUL Ronnie, or rams, FRANCE IMPLEMENT FOR MEASURING THE HARDNESS OF METALS Application filed October 21, 1827, Serial No. 227,796, and in France November 2, 1926.

The present invention relates to an implement designated a scleroscope whereby the hardness of a metal under test may be observed at once by a reading upon a graduated scale.

Known implements are in use for measuring the hardness of metals, in which a steel ball is dropped from a given height upon the surface of the test specimen, the ball rebounding to difierent heights according to the degree of hardness of the metal. The height of the rebound is then measured, and the corresponding hardness is determined from a table. However, such implements require careful manipulation, and their use is confined to the laboratory.

The implement according'to my invention has, on the contrary, a substantial constructionand affords exact observations. The desired values can at once be read, and by its use I am enabled to make a series of measurements which are quite comparable, in a very short time. The implement is based, as before, upon the elastic deformation of a hard body of suitable shape underthe action of a given impact, and the height to which the said body rebounds will show the degree of hardness of the metal under test.

However, the essential feature of the improved implement consists in the fact that when the impact member rebounds afterits impact upon'the test specimen, it will be held automatically at the maximum height which it reaches during the rebound, which height,

degree of hardness of the metal. When the impact member is thus held, it can no longer descend, though it is enabled to rise freely, so that it can only be made to drop again for the next test after it has been brought back into the initial position from which it was first dropped, and in this way itwill always fall from a constant height.

The impact member may consist of a rod or spindle which can be freely dropped in the interior of a guiding device, and which .is provided at its lower end with a hard metal piece which may be separably secured theretoand at its upper end with a suitable as above stated, corresponds exactly to the head or abutment which is justable.

In the accompanying drawing, Figure 1 is a longitudinalsectional view of a preferred form of implement embodying my 65, invention, and Fig. 2 is a cross-section thereof on line 2-2, but with the impact member and connected parts in dotted lines.

As shown in the drawing, the improved implement comprises a drop rod 1 constituting the aforesaid impact member and carrying at its lower end a steel ball 2 disposed within a socket 3 that is screwed on the rod end. The rod is guided in a tube 5 on whose lower end is screwed a cap 6, and on whose upper end a sleeve 8 is mounted; said sleeve having a threaded cap 7 fitted on it.

At the upper part of the implement two clutches or analogous coupling or retaining devices are provided, one of which serves to hold the rod in the position into which it has rebounded after having been dropped upon the surface of the test piece of metal; while the other device is utilized tohold the rod at the height to which it has been raised at the start and from which it is to make its drop. The device first mentioned consists of the sleeve 8 which has its inner wall shaped to form a tapered surface 8' for 00- 0 action with a set of steel balls 9 mounted in a cage or carrier 10 having slots 10 to receive the balls, which latter can thus be jammed between the tapered surface 8 of the sleeve and the surface of the rod 1. The cap 7 is formed with a central opening wherethrough the cylindrical top part of the cage 10 projects, such part being cut away or slotted at 10 to produce a resilient or spring action.

The cage is mounted to have a slight axial or vertical sliding movement within sleeve 8 to effect the clutching or unclutching action of the balls, according to the direction of movement, but it is normally held preferably adagainst displacement by means of an annular spring 11 which is fitted in a circumferential seat or groove in an enlarged part of the cageand is designedto bear against the inner wall of the sleeve with light pressure. 7

In conjunction with this device, there is provided a head 12 which is threaded on the upper end of the drop rod so as to be v which it carries are set for action. The rod can be readily lifted by me'ans of its head 12; and when it has reached the end or" its movement the socket 3 will strike against the cage and raise it slightly, whereupon the clutch balls will be released, the socket pret erably having its: upper end enlarged or flanged as indicated at-26.

The other crevice previously referredto consists of a catch or trigger 21 pivoted intermediate its ends on a pin 22 that is mounted vertically in a collar 23 that en'- circles the upper part of the guide tube5; such collar having an appreciably larger diii -meter than the tube andbeingmou-nted to slide thereon with a'slight degree of friction so that it will be held in adjusted position. The tube 5 is provided with front and rear longitudinal slots and which are located diametrically opposite each other and the former of which enables an inspectio'nof the movementsof the drop rod 1 and, in particular, its rebound the" collar 23bein so arrangedwith relation to this slot asnot to cover it. They catch 21 is of arcuate shape, as represented in Fig 2, and is'disposed in the space within said collar between the side wallof the latter and the tube 5,.and'i-t' is provided at one end with alug orpuslr-piece 21" that projects out ward through opening in the collar well, andat its other end with a. nose 21"'tha't projects inward through the slot 20* into position to engage beneath the. flange 26 on the socket?) and, thussupport the latter and, hence, the droprod l inq'raisedposition before the drop is made. The catch has a spring. .24 associated with it whereby its nose end isnormally forcedinward;

i. To measure and indicate the extent of the rebound of the drop rod, as well as to enable the rod to be positioned accurately for the drop, a suitable scale or scales may be provided at some desired point or points on the implement. In the present instance, the drop rod itself is graduated for that p urpo'se, the c'omplemental element in that case being" the top face'oflf the projecting upper end of the ball cage 10. an raking sheet which the air contained in the tube creasin 5 mighthave 'on the movements ofthelrod and which would, n consequence, impair the accuracy of the tests and the readings, can be avoided by forming perforations or vents in the lower portion of the tube, as indicated at 14. I

The operation is substantially as tollows:-The rod 1 is moved upward far enough to enable the catch 21 to engage the flanged edge 26 of the ball socket 3, it beingunderstoocL-of course, thatthe collar 23 whichc'arricsoth'e' catch has previously been adjusted to, dispose said catch at the desired height. The rod will thus be held in proper position for the -t'est, and the implement can then be placed in contact at its lower end with the surface of the" piece of metal to be tested, whereupon the lug 2lon the catch 18 pushed inward. This disengage-s the nose 21 from the socket 8, whereupon the rod drops of its own weight and the ball 2 strikes against thetest piecef Just as,- or before, the rod reaches the end;

of its down-stroke, its head 12 hits against the cageIO, forcing it slightly downward and setting the balls 9, read-yto clutch the rod; The rod rebounds immediately upon strikingthe test piece, and assoon as it reached the upward hunt or its movement and is about to descend; it will be gripped by the clutch balls and -held;statio1rary The height of the rebound can thenbe read from i the scale and compared with the table of hardness values' p K g For the next operation, the rodmust first be raised far enough for thesocket V3 to strike against the: bottom oi gthe] cage 10, thereby raising the same and, withit, the

balls 9' which are unclutchfrom the rod.

The latter is thenn lowered untilits socket rests upon the catch, so that when sa d catch is,released,the rodwill fall-and the cycle of operations described" above will be repeated. The effective stroke either-0d can be varied to a slight degree independently a of the adjustment of collar, 23, byadju'sting the position of the lower cap 6 on the-guide tube,- said cap having threaded engagement I with the'tube, -as has been stated.

Icl'aimasmy invention:

1. A s'cleroscope, compr1s1ng aguide' tube;

an impact rod i movablethereina'and adapted to be dropped upon the surface oi a test piece; aball clutch" acting automatically to engage and locksai'd'rodlat the top of its o rebound; anda controlling device mounted upon the upper part of the-rod for operating on said clutch and embodying a head adjustably positioned on the rod."

2 A scleroscope, comprising a guide tube}; an impact rod movable therein and adapted to be dropped upon the'suriace of a test piece; a ball clutch mo'unted in the upper part of thetube for automatically locking saidrod at the I top or its rebound, said clutch including.- a movable cage; and a head adjust-ably mounted upon the upper part of the rod to strike against and thereby shift said cage into operative position at the end of the drop.

3. A scleroscope, comprising a guide tube; an impact rod movable therein and adapted to be dropped upon the surface of a test piece; and freely-adjustable means for regulating the height of the drop, said means embodying a ring encircling the tube and adjustable vertically thereon, and a springpressed catch carried by the ring and engageable With a part provided on the rod.

4. A scleroscope, comprising a guide tube; a rod movable therein and adapted to be dropped upon the'surface of a test piece, said rod being provided at its lower end With a socket having an impact ball therein; and freely-adjustable means for regulating the height of the drop, said means embodying a ring encircling the tube and adjustable vertically thereon and a springpressed catch carried by the ring and engageable With the socket.

5. A scleroscope, according to claim 4, in Which the socket is provided With an outwardly-extending flange, and the catch has an inwardly-extending nose to engage under said flange.

In testimony whereof I afiix my signature.

PIERRE PAUL ROUDIE. 

